1. Field of the Invention
This invention relates to adjustable headgear and more particularly to adjustable headgear capable of two-point and four-point connections with a gas delivery mask.
2. Description of the Prior Art
Headgear is known by which a gas delivery mask is maintained in contact with the face of a patient. Such headgear has incorporated upper and lower straps, each having opposite ends threaded through connector elements provided on the opposite sides and the top of a mask. Each strap includes releasable securing means, for example, a Velcro.RTM. fastener, such that each strap may be adjusted as required to produce an effective seal between the mask and the patient's face.
Three such headgears are marketed by the assignee of this invention, i.e., RESPIRONICS, INC. One such headgear utilizes a rectangular plastic card adapted to reside on the back of a patients head and to which the upper and lower straps are secured, for example, by means of Velcro.RTM. fastener. Such a headgear is described and illustrated, for example, in a brochure entitled "RESPIRONICS SleepEasy.RTM. Nasal CPAP System" published by RESPIRONICS, INC., and dated Jan. 30, 1986. The mark "SLEEPEASY" is a trademark of RESPIRONICS, INC.
In a second headgear type, a crown strap spans between the end portions of the upper strap. A back strap is secured at one end to the crown strap and extends therefrom downwardly and interiorly of the upper and lower straps and then upwardly and outwardly of the lower and upper straps to enclose the same. Both the crown strap and the back strap are adjustable to conform the headgear with the shape and size of the patients head. Such a headgear is illustrated, for example, in an instruction sheet for Item No. 302044, entitled "Headgear Instructions for Use" published by RESPIRONICS, INC., and dated Jun. 12, 1990.
In a third headgear type, a hood-shaped cap is provided wherein upper strap segments are attached to the cap so as to be disposed above the ears of the patient; and wherein lower strap segments are attached to the cap along a bottom edge thereof. Such a headgear is illustrated, for example, in an instruction sheet for Item Nos. 302142 and 3022, entitled "Softcap.TM. Instructions for Use" published by RESPIRONICS, INC., and dated Jun. 1, 1990. The mark "Softcap" is a trademark of RESPIRONICS, INC.
In each of the three headgear examples described above, there is no stabilizing connection between the upper and lower straps. In the third headgear example described above, there is no stabilizing connections between the hood-shaped cap and the lower strap segments.